1. Field of the Invention
The present invention relates to a liquid crystal panel, and in particular, to a technique for reducing the number of times of application of exposure in a process of manufacturing the same.
2. Description of the Related Art
In an in-plane switching liquid crystal panel, a pixel electrode and a common electrode (opposed electrode) are both formed on one substrate where a thin film transistor is formed. As described in International Publication No. WO2001/018597, this kind of liquid crystal panel includes one of a type in which a common electrode is formed in the uppermost layer except an alignment layer film, and other conductor layers, such as a pixel electrode, a signal line, and so forth, are formed in layers lower than the common electrode. In this type, an electric field generated by a voltage applied to a video signal line (drain line) can be shielded by using the common electrode. Consequently, a black matrix for hiding influence of an electric field on displayed image can be reduced in its width and thus an aperture ratio of a pixel can be improved.
A substrate of a liquid crystal panel is generally manufactured using a photolithographic method. In the photolithographic method, a resist film is patterned on an insulating film and a conductor film at exposure processes, and the insulating film or the like is etched using the resist film as a mask.